On Sat, 26 Feb 2022 19:17:46 +0100, you wrote: >Dne sobota, 26. februar 2022 ob 18:59:18 CET je Jernej Škrabec napisal(a): >> Hi! >> >> Dne petek, 25. februar 2022 ob 20:30:20 CET je Jernej Škrabec napisal(a): >> > Hi! >> > >> > Dne petek, 25. februar 2022 ob 17:45:55 CET je Benjamin Gaignard >napisal(a): >> > > The number of 'entry point offset' could be very variable. >> > > Rather than use a large static array define a v4l2 dynamic array >> > > of integer control. >> > >> > I suggest we should be more specific and say U32 (V4L2_CTRL_TYPE_U32). >> > >> > > The number of entry point offsets is reported by the elems field. >> >> I did few more tests and these are my findings: >> 1. dynamic array can't be set over size, specified in .dims array >> 2. entry point offsets are per slice, so if we make slices dynamic array, >then >> entry points would become two dimensional dynamic array >> 3. num_entry_point_offsets must be part of slice control, because it can be >> zero, but size of array can't be > >Clarification: num_entry_point_offsets is needed in any case, even without entry >point list. I thought that at least one decoder wanted the entry points or have we decided that we don't? Whilst they aren't required for decode, what they give you, if your h/w supports it, is the ability to decode multiple lines of CTBs in parallel (with a 2 CTB offset between lines), so they aren't useless. If we do decided we want the entry point offset control, now or later, then num_entry_points in the slice_param allows you to determine which offsets apply to which slices without the complexity of a variable array of variable arrays. But whether or not we end up supporting entry point offsets, the Pi h/w requires me to generate 1 table entry for each CTB line and num_entry_points is the parameter I need for that, so I really want it in the slice_params. Regards John Cox >> 4. fortunately, not setting entry points doesn't impact decoding >correctness. >> This is in line what John told me about them. >> >> Hans, can you comment points 1-3? I might misunderstand point 1. >> >> In short, it seems like we don't really need entry points, even if they are >> used in BSP library. In both cases, I got fluster score 119/138 (10-bit >> excluded), so we can just drop this patch, although I'm a bit uneasy not >> setting entry points... >> >> Best regards, >> Jernej >> >> > > >> > > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxxxxx> >> > > --- >> > > .../userspace-api/media/v4l/ext-ctrls-codec.rst | 9 +++++++++ >> > > include/media/hevc-ctrls.h | 1 + >> > > 2 files changed, 10 insertions(+) >> > > >> > > diff --git a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst b/ >> > Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst >> > > index 44a268a948c0..71f7dc1c1ccd 100644 >> > > --- a/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst >> > > +++ b/Documentation/userspace-api/media/v4l/ext-ctrls-codec.rst >> > > @@ -3128,6 +3128,15 @@ enum v4l2_mpeg_video_hevc_size_of_length_field - >> > > >> > > \normalsize >> > > >> > > +``V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSETS (integer)`` >> > >> > Here you have OFFSETS (plural) ... >> > >> > > + Specifies the i-th entry point offset in bytes and is represented by >> > > + offset_len_minus1 plus 1 bits. >> > >> > You probably mean entry_point_offset_minus1? offset_len_minus1 just tells >how >> > much bits need to be read for each element and it's not important for >actual >> > decoding. >> > >> > > + This control is a dynamically sized array. The number of entry >point >> > > + offsets is reported by the ``elems`` field. >> > > + This bitstream parameter is defined according to :ref:`hevc`. >> > > + They are described in section 7.4.7.1 "General slice segment header >> > > + semantics" of the specification. >> > > + >> > > ``V4L2_CID_STATELESS_HEVC_SCALING_MATRIX (struct)`` >> > > Specifies the HEVC scaling matrix parameters used for the scaling >> > process >> > > for transform coefficients. >> > > diff --git a/include/media/hevc-ctrls.h b/include/media/hevc-ctrls.h >> > > index 3016c1abb1d0..3f8a67924df3 100644 >> > > --- a/include/media/hevc-ctrls.h >> > > +++ b/include/media/hevc-ctrls.h >> > > @@ -20,6 +20,7 @@ >> > > #define V4L2_CID_STATELESS_HEVC_DECODE_PARAMS (V4L2_CID_CODEC_BASE + >> > 1012) >> > > #define V4L2_CID_STATELESS_HEVC_DECODE_MODE (V4L2_CID_CODEC_BASE + >> > 1015) >> > > #define V4L2_CID_STATELESS_HEVC_START_CODE (V4L2_CID_CODEC_BASE >+ >> 1016) >> > > +#define V4L2_CID_STATELESS_HEVC_ENTRY_POINT_OFFSET (V4L2_CID_CODEC_BASE >+ >> > 1017) >> > >> > ... and here you have OFFSET (singlular). I suggest plural form to be used >> in >> > all places, including subject line of this commit. >> > >> > Additionally, it would be nice if control is initialized, like so: >> > https://github.com/jernejsk/linux-1/commit/ >> > f938e162cd8dd77c9f6f1b248d80144840a37bce >> > >> > Best regards, >> > Jernej >> > >> > > >> > > /* enum v4l2_ctrl_type type values */ >> > > #define V4L2_CTRL_TYPE_HEVC_SPS 0x0120 >> > > -- >> > > 2.32.0 >> > > >> > > >> > >> > >> > >> >> >> >
